Field of the Invention
The invention relates to gas turbine engine rotor disks and, particularly, to rotor disks used in the gas turbine engine fan and the booster stages.
Description of Related Art
Gas turbine engine metallic rotor disks are generally used to hold blades. The rotor disks in the fan and the booster stages carry significant centrifugal radial forces and, therefore, often have axial slots for blade retention. The radial forces generate both radial and tangential stresses during engine operation. In addition, fan blade out FBO or blade-out events can introduce high loads. The relatively heavy weight of the metallic rotor disks increase the loading and stresses.
Composite integrally bladed rotors for use in gas turbine engines have been disclosed in several patents such as U.S. Pat. Nos. 4,747,900, 4,786,347, and 7,491,032. Composite integrally bladed rotors are subject to large forces which must be taken into account in designing the construction of the rotor to preserve its integrity. In the rotor disk area, the major forces are exerted in circumferential directions so an ability to absorb hoop stress is important, whereas, in the airfoil blades radially exerted forces predominate. Composite material used in such rotors typically include a resin (such as epoxy) which has low inherent strength. The composite material has a specific strength higher than that of metal due to the inclusion of fibers normally of the same material embedded in a matrix of the composite material. The fibers are known to be strongest in tension so the direction of the forces in the finished component will, at least in part, determine its strength.
It is highly desirable to have a design for and method for manufacturing light-weight, strong, and easy to manufacture gas turbine rotor disks. It is also desirable to have a rotor with easy to assemble and disassemble composite blades. It is also desirable to have an easy to service rotor with composite blades that can be individually serviced if one is damaged.